Recent Modalities in the Diagnosis of Obesity

Obesity has been an emerging health problem worldwide which has a major impact on public health. It is associated with medical, psychosocial and economic implications with increasing prevalence among both adult and paediatric population. Obesity led to an increased risk of medical conditions like diabetes mellitus, hypertension, coronary artery disease, insulin resistance and sleep apnoea. Obesity has a major impact on cardiovascular system causing structural and functional changes leading to cardiac dysfunction. Hence it is important to diagnose obesity at the earliest for timely prevention of associated complications. Apart from routine diagnostic methods for obesity like body mass index, anthropometry (waist circumference, hip circumference, neck circumference), several recent modalities were described for the diagnosis of obesity like radioimaging, nuclear medicine imaging which will be described in detail in this review article. MRI (Magnetic resonance imaging) aids in the detection of adipose tissue at various sites and organs, whereas MRS (Magnetic resonance spectroscopy) helps in mapping of small quantity of lipids. MRI helps in delineating ectopic adipose tissue accumulation establishing that obesity alone is not a major cause for derangement in metabolic profile. An additional advantage is MRI brain is an excellent imaging guide for studying the role of central appetite regulatory systems in the occurrence of obesity. Sonography is not accurate in the estimation of hepatic steatosis. But advancements in sonographic modalities gives an extra edge in evaluation of hepatic steatosis by availing special physical characteristics such as stiffness of adipose tissue and its sound absorption. Positron Emission Tomography (PET) (Nuclear medicine imaging) helps in studying central pathophysiology, activity of brown adipose tissue and disruption of gut-brain homeostasis.

Tumor-Specificity Growth Factor Combined with Tumor Markers in Nuclear Medicine Imaging to Identify Prostate Cancer Osteonosus

Objective. This study has explored the application value of malignant tumor SPE growth factor (TSGF) combined with tumor markers (TM) (TSGF + TM) in nuclear medicine imaging to identify prostate cancer osteonosus (PCO). Methods. A retrospective analysis for 70 patients with prostate cancer and bone disease admitted to our hospital was performed, 30 healthy persons in the same period were selected as the control group, and the advantages and disadvantages of various examinations were analyzed. All patients were diagnosed with PET whole body bone imaging. Suspicious lesions could be examined by MRI or CT. According to the results of imaging examination, patients were divided into 40 cases of malignant prostate cancer and 30 cases of benign prostate cancer. All the patients underwent 18F-FDG-PET imaging, alpha-fetoprotein (AFP), and TSGF + TM determination. The case diagnosis results were compared and analyzed, and the sensitivity (SEN), specificity (SPE), and accuracy (ACC) of various detection methods were calculated. The SEN, SPE, and ACC of positron emission tomography (PET) were 90.9%, 57.8%, and 81.2%, respectively; those of TM were 79.2%, 94.6%, and 69.8%, respectively; and those of TSGF + TM were 95.9%, 100%, and 97.3%, respectively. The accuracy of combined diagnosis of tumors can reach 100%. The AFP and TSGF levels of serum TM were compared and analyzed, and it was found that the benign lesion group and the malignant lesion group showed significant increases compared with the control group, and the difference between the malignant lesion group and the control group was obvious ( P < 0.05). SGF combined with TM could obtain a more definite diagnosis in PCO. Conclusion. TSGF + TM combined with 18F-FDG-PET imaging showed important clinical value to diagnose the PCO. The imaging accuracy of TSGF + TM combined with 18F-FDG-PET is 97.3%, and the specificity of tumor diagnosis is 100%. Therefore, the TSGF + TM applied in medical imaging and identification of PCO was worthy of clinical promotion.

68Ga-DOTATATE PET in Pediatric Paraganglioma / Pheochromocytoma: A Case-series Highlighting the Role of Functional Imaging

Pheochromocytoma and paraganglioma (PPGL) are rare neuroendocrine tumors in childhood. Cancer predisposition syndromes (CPS) are increasingly recognized as the underlying cause for a number of pediatric malignancies and up to 40% of PPGL are currently thought to be associated with a hereditary predisposition1,2. With the increasingly widespread availability of functional molecular imaging techniques, nuclear medicine imaging modalities such as 18F-FDG-PET/CT, 123I-MIBG SPECT/CT, and 68Ga-DOTATATE PET/CT now play an essential role in the staging, response assessment and determination of suitability for targeted radiotherapy in patients with PPGL. Each of these imaging modalities targets a different cellular characteristic, such as glucose metabolism (FDG), norepinephrine transporter expression (MIBG), or somatostatin receptor expression (DOTATATE), and therefore can be complementary to anatomic imaging and to each other. Given the recent FDA approval3 and increasing use of 68Ga-DOTATATE for imaging in children4, the purpose of this article is to use a case-based approach to highlight both the advantages and limitations of DOTATATE imaging as it compares to current radiologic imaging techniques in the staging and response assessment of pediatric PPGL, and to offer a decision algorithm for the use of functional imaging that can be applied to PPGL, as well as other neuroendocrine malignancies.

Brain Neuroimaging of Rapid Eye Movement Sleep Behavior Disorder in Parkinson’s Disease: A Systematic Review

Background: REM-sleep behaviour disorder (RBD) is a parasomnia and a common comorbidity in Parkinson’s disease (PD). There is evidence that the presence of RBD is associated with more severe PD. The differences in the clinical manifestations and the natural history are likely to imply underlying differences in the pathophysiology among PD patients with and without RBD. The increasing number of neuroimaging studies support this notion. Objective: Our primary objective was to review the current evidence regarding the brain neuroimaging findings in PD patients with RBD (PDRBD). Methods: A systematic review of articles, published in PubMed between January 1, 2000 and September 23, 2020 was performed. We evaluate previous studies that assessed PD patients with RBD using various brain structural and functional magnetic resonance imaging (MRI) techniques and brain nuclear medicine imaging. Results: Twenty-nine studies, involving a total of 3,347 PD subjects among which 912 subjects with PDRBD, met the selection criteria and were included. The presence of RBD in PD patients is associated with structural and functional alterations in several brain regions, mainly in brainstem, limbic structures, frontotemporal cortex, and basal ganglia, raising the hypothesis of a PDRBD neuroimaging phenotype. Conclusion: The current review provides up-to-date knowledge in this field and summarizes the neurobiological/neuroimaging substrate of RBD in PD.

Prospective Quantitative Neuroimaging Analysis of Putative Temporal Lobe Epilepsy

Purpose: A prospective study of individual and combined quantitative imaging applications for lateralizing epileptogenicity was performed in a cohort of consecutive patients with a putative diagnosis of mesial temporal lobe epilepsy (mTLE).Methods: Quantitative metrics were applied to MRI and nuclear medicine imaging studies as part of a comprehensive presurgical investigation. The neuroimaging analytics were conducted remotely to remove bias. All quantitative lateralizing tools were trained using a separate dataset. Outcomes were determined after 2 years. Of those treated, some underwent resection, and others were implanted with a responsive neurostimulation (RNS) device.Results: Forty-eight consecutive cases underwent evaluation using nine attributes of individual or combinations of neuroimaging modalities: 1) hippocampal volume, 2) FLAIR signal, 3) PET profile, 4) multistructural analysis (MSA), 5) multimodal model analysis (MMM), 6) DTI uncertainty analysis, 7) DTI connectivity, and 9) fMRI connectivity. Of the 24 patients undergoing resection, MSA, MMM, and PET proved most effective in predicting an Engel class 1 outcome (&gt;80% accuracy). Both hippocampal volume and FLAIR signal analysis showed 76% and 69% concordance with an Engel class 1 outcome, respectively.Conclusion: Quantitative multimodal neuroimaging in the context of a putative mTLE aids in declaring laterality. The degree to which there is disagreement among the various quantitative neuroimaging metrics will judge whether epileptogenicity can be confined sufficiently to a particular temporal lobe to warrant further study and choice of therapy. Prediction models will improve with continued exploration of combined optimal neuroimaging metrics.

Efficient Strike Artifact Reduction Based on 3D-Morphological Structure Operators from Filtered Back-Projection PET Images

Positron emission tomography (PET) can provide functional images and identify abnormal metabolic regions of the whole-body to effectively detect tumor presence and distribution. The filtered back-projection (FBP) algorithm is one of the most common images reconstruction methods. However, it will generate strike artifacts on the reconstructed image and affect the clinical diagnosis of lesions. Past studies have shown reduction in strike artifacts and improvement in quality of images by two-dimensional morphological structure operators (2D-MSO). The morphological structure method merely processes the noise distribution of 2D space and never considers the noise distribution of 3D space. This study was designed to develop three-dimensional-morphological structure operators (3D MSO) for nuclear medicine imaging and effectively eliminating strike artifacts without reducing image quality. A parallel operation was also used to calculate the minimum background standard deviation of the images for three-dimensional morphological structure operators with the optimal response curve (3D-MSO/ORC). As a result of Jaszczak phantom and rat verification, 3D-MSO/ORC showed better denoising performance and image quality than the 2D-MSO method. Thus, 3D MSO/ORC with a 3 × 3 × 3 mask can reduce noise efficiently and provide stability in FBP images.

Comparative Study of Various Nuclear Medicine Imaging Technique - A Review

Nuclear Medicine is a medical specialty that allows modern diagnostics and treatments using radiopharmaceuticals original radiotracers (drugs linked to a radioactive isotope). The radiopharmaceuticals are considered a special group of drugs and thus their preparation and use are regulated by a set of policies that have been adopted by individual member countries. The radiopharmaceuticals used in diagnostic examinations are administered in very small doses. So, in general, they have no pharmacological action, side effects or serious adverse reactions. The most serious issue with their use is the potential for diagnostic mistakes due to changes in their biodistribution. The appearance and development of new radiopharmaceuticals in both the diagnostic and therapeutic domains, as well as the impact of new multimodality imaging techniques, are all having a significant impact on nuclear medicine (SPECT-CT, PET-CT, PET-MRI, etc.). It is crucial to understand the techniques limitations, radiopharmaceutical distribution and potential physiological changes, radiological contrast contraindications and bad responses, and the possibility of both interfering. The process of generating radiopharmaceuticals is introduced and relevant interactions of radiation with matter are discussed. Diagnostic nuclear medicine instrumentation is explained, and future trends in nuclear medicine imaging technology are forecasted.